This invention relates to an energy absorbent vehicle bumper having a support on the vehicle, A covering over the support and energy absorption means between them. In addition, the invention concerns retention of the covering over the support in the event of impact upon the covering mechanism.
To avoid panel damage to vehicles from collisions occurring during parking maneuvers, in traffic jams, in confined garages, etc., the vehicles are fitted with bumpers which are capable of absorbing the impact of a collision up to a certain speed without damage to the vehicle. A conventional vehicle bumper incorporates a strong steel bar which extends across the vehicle and is secured to the supporting elements of the vehicle. A continuous elastic casing conceals the steel bar and an energy absorbing mechanism is secured to the rail. To prevent the casing from loosening and becoming torn off in a manner dangerous to other traffic in the event of a collision, the casing is secured to the steel bar with a relatively large number of bolted joints. The bolted joints render the bumper more expensive to produce and complicate its assembly.
To simplify assembly of a bumper, German patent specification DE 27 02 691 A discloses a bumper casing with continuous hooks which slide into corresponding recesses in the rail so that they lock. This solution obviously simplifies the bumper assembly, but it is unsuitable in terms of road safety because the hooks can easily be deformed in the event of a collision, causing the casing to become detached from the rail.
British patent GB 2,151,993 C, in FIG. 3, shows a bumper with a casing constructed with V-shaped openings, each of which clamps round one edge of a rail that is firmly secured to the vehicle. The purpose of this design is to prevent the casing from being ripped off vertically in the event of a collision. But, because the interaction between the respective V-shaped openings and the edge is alone unable to prevent vertical displacement of the casing, the energy absorbing mechanism must consist of a foam which is sprayed into the entire continuous space between the casing and the rail and which, when it solidifies, adheres to both the rail and the casing to ensure that the bumper forms one coherent unit.
Manufacture of the foregoing bumper involves the use of complicated production equipment which increases the cost of the bumper. Moreover, because the energy absorbing material is secured to both the casing and the rail, it is impossible merely to replace the part that became damaged after a minor collision. Instead, the entire bumper must be replaced, which is obviously unnecessarily costly to the owner of the vehicle.